Actually, I've never had a problem removing minifig arms or legs. I've been rippin 'em off for so many years I just kind of do it now. For arms, I go in at a slight angle, then straight and push. It helps to attach the hand first. For legs, move both legs as far apart away from each other as possible, the grab and pull while twisting. It helps to attach a torso/shirt first also.

And teeth are VERY useful, I don't know where I'd be today without my teeth. Jaw muscles are powerful, and if you grab a stud or something and clench down with your teeth and pull with your hands and head, it's very easy to pull anything apart. I've never had to buy a brick remover, and even if you guys don't use your teeth, don't buy one. A butter knife works just as well.